Joe Nathan, Francisco Liriano and Boof Bonser for A.J. Pierzynski (2003)
This one was a bad trade both short-term and long-term. The team brought in a catcher in A.J. Pierzynski who clashed with his teammates, and had a year well below what the Giants were hoping for.
He had three years left of arbitration and was coming off a year in which he hit .312 and had better numbers overall then the previous year when he made the All-Star team. He hit .272 with the Giants in 2004 and was eligible for arbitration.
Pierzynski didn’t get along with several teammates, prompting anonymous calls for him to be traded. The team released him after the season even though he was arbitration eligible for three more seasons.
They also gave up three young arms, one in particular who dominated the closer’s role for several years. This was Brian Sabean’s one real blemish in his career as a general manager.
Joe Nathan went on to become an elite closer with the Twins starting with that next year (44 saves). In 7 years with the team, he had 260 saves (franchise record), with a 2.16 ERA and appeared in 4 All-Star games with them. Nathan was also a two-time All-Star with the Texas Rangers.
Francisco Liriano was a high-ceiling prospect in the Giants system, with an electric fastball, and ace-quality stuff. But he was also a risk, as his delivery increased the chances that he would develop arm trouble. Liriano made his only All-Star game in 2006, going 12-3 in 16 starts. But he missed 2007, and his consistency has suffered ever since. He ended his tenure with the Twins with a 50-52 record and a 4.33 ERA. (He has been better the last couple of years with the Pittsburgh Pirates)
Boof Bonser was a starter who opened some eyes in his second year in the minors with a 16-4 record and a 2.49 ERA. The former first rounder went on to pitch three years with the Twins after the trade, going 18-25 with a 5.12 ERA. He came back to the Giants in 2013 and pitched 15 games in Fresno.
Next: Giants Get Duffy